圆钢管活性粉末混凝土轴压力学性能研究

进行22根圆钢管活性粉末混凝土轴压短柱试验,分析其荷载-变形曲线、破坏特征和工作全过程。试验研究表明:圆钢管RPC轴压短柱的荷载-纵向应变曲线弹性阶段约为极限荷载的90%~95%;套箍系数ξ较小时,在达到极限荷载后承载力急剧下降;ξ较大时,在达到极限荷载后承载力下降平缓并呈回升趋势。ξ较小的试件多呈剪切破坏形态;ξ较大的试件所有断面上均被墩粗、试件的上下两端明显局部鼓曲。在分析国内40个试件试验结果的基础上,研究建立了圆钢管活性粉末混凝土峰值应力、峰值应变、平台应力等理论特征参数的计算方法和应力-应变全曲线方程,验证对比了有关技术规程中圆钢管混凝土基本构件承载力的计算方法,最后建议了圆钢管活性混凝土轴压短柱极限承载力统一计算公式。

Research on behavior of RPC filled circular steel tube column subjected to axial compression

Based on the experimental study of 22 reactive powder concrete(RPC) filled circular steel tube columns subjected to axial compression, this paper analyses the load versus displacement curves, the failure patterns and the all course of work. The results show that the elastic region of the load versus strain curves is about 90%-95% of the whole, specimen with low confinement factor () exhibits a rapid softening process in the post-peak region, and a brittle shear failure, while specimen with high confinement factor exhibits a gradual softening process in the post-peak region, and causes serious bulge in all sections and significant buckling on the top and bottom of the specimen. Based on analyzing the test results of 40 specimens at home, this paper also presents the calculation formula of the theory-character parameters (peak stress, peak strain and plateau stress) for RPC filled circular steel tube and the equation for complete stress-strain curve. Calculation methods of concrete filled circular steel tube in different codes are checked and contrasted, finally the calculation formula for ultimate loading capacity of RPC filled circular steel tube columns under axial compression is proposed.